Improve workflow, use new actions and also cache

.github/workflows/image.yml

@@ -10,11 +10,22 @@ jobs:
     steps:
       - name: checkout code
         uses: actions/checkout@v2
-      - name: install buildx
-        id: buildx
-        uses: crazy-max/ghaction-docker-buildx@v1
+      - name: Cache Docker layers
+        uses: actions/cache@v2
+        id: cache
         with:
-          version: latest        
+          path: /tmp/.buildx-cache
+          key: ${{ runner.os }}-buildx-${{ github.sha }}
+          restore-keys: |
+            ${{ runner.os }}-buildx-        
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+        with:
+          config-inline: |
+            [worker.oci]
+              max-parallelism = 16
       - name: Login to DockerHub
         uses: docker/login-action@v1
         with: